Postcards Mailing Services USA - In the U.S. A, most people normally receive custom printed postcards by direct mail six out of seven days a week. In Canada, it's 2 to 5 days a week depending on the geographical location. Options are great that on any given delivery day, some of the postcards collateral will be in your mailbox. What is the reason they deliver highly profitable returns. If you believe a direct mail campaign does not work anymore then why do so a lot of small and big and companies use postcard printing services as a primary marketing strategy to create more business.